Based on the overview of ASTM E562-19, the following recommendations are made:
is the "Standard Test Method for Determining Volume Fraction by Systematic Manual Point Counting." Feature: Systematic Manual Point Counting (ASTM E562-19) astm e56219 pdf
The standard requires a total of at least 400 to 1,000 counts (points) to achieve a 95% confidence level. For low-volume phases (e.g., 5% area), you may need to count 2,000+ points. Based on the overview of ASTM E562-19, the